The difference between Stage I and Stage II cataract IOLs is the timing and method of surgery. Stage 1 cataract IOL is the implantation of an IOL directly after the removal of the cloudy lens, while Stage 2 IOL is the implantation of an IOL after the removal of the lens and the stabilization of the patient’s condition. Cataracts are usually caused by clouding of the human lens, which leads to abnormal visual transmission and thus affects vision. However, most cataracts can be restored with IOL implantation. Generally, if the patient only has a cloudy lens, an IOL can be implanted directly after the removal of the cloudy lens, which is known as Phase I IOL implantation. Phase II implantation is to correct the refractive error of aphakic eyes or IOLs after the removal of the original lens. Different surgical methods are suitable for different cataract patients, and the specific method should be decided by the doctor after examination. It is recommended that patients go to the ophthalmology department of a regular hospital for consultation, complete the relevant examinations, and choose the appropriate treatment under the guidance of the doctor.